The proposed study will use qualitative methods to examine the factors impacting primary care providers' and patients' pain management practices in clinical settings and patients' home communities. Chronic non-cancer pain (CNCP), which affects 25% of American adults, is a leading cause of disability and exorbitant health care costs in the United States. Low income patients, who access primary care services in safety net health systems, are more likely to be diagnosed with CNCP than their insured counterparts. CNCP patients with histories of substance use are the highest frequency users of prescribed opioid pain medications with the least access to pain and mental health specialist care. The Institute of Medicine and the American Pain Society have concluded that a dearth of scientific research exists to guide primary care providers' (PCPs') pain management practices, particularly with substance-using patients at high risk for opioid misuse and morbidity and mortality associated with accidental overdose. Arthur Kleinman's model for the anthropological study of pain management suggests that Western clinical health practices encompass individual, interactive and socio- structural dimensions which all influence health outcomes. Pain management practices take place in specific and widely divergent social contexts: the clinic where pain is discussed and responded to biomedically and home environments where patients cope with pain on an everyday basis. By adapting Kleinman's model to target CNCP patients with histories of substance use and their PCPs, the proposed qualitative study will provide needed contextual, observational data to inform CNCP pain management for this high-risk, under- researched patient group. The Specific Aims are: Aim 1: To explore primary care providers' pain management practices in safety net clinical settings with patients who have a history (past or current) of substance use. Aim 2: To explore patients' pain management practices in clinical settings. Aim 3: To explore patients' pain management practices in their home environments. The study will take place in six safety net clinics and patients' home environments in three diverse San Francisco Bay Area Counties. For Aim 1 we will conduct (a) qualitative interviews with 20 PCPs and (b) clinical observation of pain management interactions between the 20 PCPs and 60 of their CNCP patients. For Aim 2, we will conduct (a) qualitative interviews with the 60 CNCP patients and (b) analyze the patient-provider clinical interaction data from the patient perspective. For Aim 3, we will conduct community-based participant observation with a theoretically-selected sample of 20 of the 60 participating patients. Qualitative data will be transcribed, coded and analyzed using grounded theory methodologies. The multidisciplinary research team, consisting of a medical anthropologist/substance use researcher (Early Stage Principal Investigator), a physician/health services researcher (Co-investigator), and a nurse/clinical pain policy expert (Co-investigator), will synthesize the data with the goal of improving our understanding of CNCP management to inform future research and clinical practice.